fix: align the look of Priority section in task modal with date sections

[ilandikov]

Description

In Priority section:

• Use color from the Obsidian for the checked radio button (Default blue -> Obsidian violet, like the checkbox for "Only future dates")
• Align the grid that positions the priority values with the date sections

Motivation and Context

Consistent look the edit task modal.

How has this been tested?

Visual test in demo vault.

Screenshots (if appropriate)

Before	After

Types of changes

Changes visible to users:

• Bug fix (prefix: fix - non-breaking change which fixes an issue)

Checklist

• My code follows the code style of this project and passes yarn run lint.
• My change has adequate Unit Test coverage.
  • no unit test for CSS code

Terms

• My contribution follows this project's contributing guide
• I agree to follow this project's Code of Conduct

[ilandikov]

I wrote the commits as feat but when creating the PR realised they are more of a fix so the PR is a fix. I can change the commit messages to fix as well and force push the branch if you prefer.

[claremacrae]

Thanks